Hydroxy-de-halogenation

A. Attack by OH at an Alkyl Carbon 10-1 Hydrolysis of Alkyl Halides Hydroxy-de-halogenation... 

The dehalogenases (EC 3.8.1), a subclass of the hydrolases that act on the halide bonds in C-halide compounds, catalyze reactions of hydrolytic de-halogenation (Fig. 11.3,a), i.e., the replacement of a halide atom at a sp3 C-atom with a OH group. Exceptions include thyroxine deiodinase (EC 3.8.1.4), which catalyzes reductive deiodination on phenyl rings, and the bacterial 4-chlorobenzoate dehalogenase (EC 3.8.1.6), which forms 4-hydroxy-benzoate. 

Migrations of Halogen, Hydroxyl, Amino, etc. Hydroxy-de-bromo-c/ne-substitution, etc. 

The DE ring of camptothecin has been prepared enantioselectively in six steps from 2-fluoropyridine using a halogen dance reaction <95TL(36)7995>. The first total synthesis of dimethyl sulfomycinamate (47) was reported starting from 3-hydroxy-6-methylpyridine (48) <95TL(36)5319>. 

Ethylene glycol haa likewise been found to condense with efji-chlorohydrin. In the absence of alkali, aim de addition at the let ni i i> il epoxide oarbon atom ocotnm, but in the prenenoe of the moncaodium ycolate a halogen-free product is isolated, which appears to be l,2-di-j6 (-hydroxy oxy)-2-pcopanol, as shown in Eq. (CBB). 

Die hydrierende Aminierung gelingt in vielen Fallen auch unter Erhalt von Ester-, Acetal-, Halogen-, N-Benzyl-, Hydroxy-Gruppen und des Furan-Ringes. 

---